Biomedical subjects

C Masciocchi

Publications and source records attributed to C Masciocchi.

At least 19 recordsLinked to original sources

PubMed2000

Musculoskeletal MRI: dedicated systems.

The "dedicated" MRI units have characteristics of high diagnostic accuracy and lower installation and management costs as compared with whole-body systems. The dedicated MRI units are easy to install. The low weight allows their installation also under unfavorable circumstances. In a dedicated system cost-effectiveness and ease of installation must be accompanied by the capability of providing high-quality images. In our experience, the high number of examinations performed, the most part of which provided with the surgical controls, allowed an accurate evaluation of the diagnostic potentialities of the dedicated magnet. We were not able to perform the examinations in only 3 % of cases due to the physical shape of the patient and the clinical condition of the patient which may hinder the correct positioning of the limb. The overlapping of the diagnostic accuracy of the E-scan and Artoscan units in the study of the lower limbs, compared with whole-body units and surgery, prompted us to exploit the potentialities of the E-Scan in the study of the shoulder. We had a good correlation between E-Scan, whole-body units, and surgical findings, which confirmed the high diagnostic accuracy of the dedicated system. In conclusion, in our experience carried out in the musculoskeletal system, the dedicated magnets showed promising results. Their diagnostic reliability and utility was comparable to that obtained from conventional units operating at higher magnetic fields.

Female↗

PubMed2000

Comparative evaluation of TEE, conventional MRI and contrast-enhanced 3D breath-hold MRA in the post-operative follow-up of dissecting aneurysms.

PURPOSE: To verify the diagnostic potentialities of conventional magnetic resonance imaging (MRI), breath-hold 3D contrast enhanced MR angiography (C3D MRA) and transesophageal echocardiography (TEE) in patients surgically treated for type A aortic dissection. MATERIALS AND METHODS: Twenty-nine patients (21 males and 8 females), surgically treated for type A aortic dissection, were evaluated with MRI using a 1.5 T (GE Horizon Echospeed 8.2) with standard gated SE sequences and breath-hold 3D fast SPGR after intravenous Gd injection (0.2 mmol/kg). 3D MIP reconstruction was obtained. TEE evaluation was performed with a HP 2000 system and a biplane 5 MHz probe. The sizes of aortic root, distal anastomosis, descending aorta and periprosthetic thickening were measured. Regional false lumen and aortic branch involvement were also evaluated. RESULTS: Concordance among TEE, conventional MRI and C3D MRA was observed in the evaluation of aortic root (MRI vs. C3D MRA r = 0.93; MRI vs. TEE r = 0.84; C3D MRA vs. TEE r = 0.84) and descending aorta (r = 0.94, 0.91 and 0.92, respectively). The interobserver variability was also very low. Inadequate agreement was observed for distal anastomosis. C3D MRA was inadequate in the evaluation of periprosthetic thickening; r = 0.73 was obtained between MRI and TEE. For qualitative data: TEE was inadequate in the evaluation of the abdominal aorta and branches. C3D MRA depicted supra-aortic vessel involvement in more cases than the other techniques. CONCLUSION: C3D MRA is a fast and accurate technique in the evaluation of the endoluminal alterations and involvement of the aortic branches. Conventional MRI allows a direct evaluation of the aortic wall and periaortic tissue. TEE is less accurate in the evaluation of aortic branches and abdominal aorta.

Adult↗

PubMed2000

[Antero-posterior lesions of the superior glenoid labrum. Magnetic resonance evaluation].

PURPOSE: To assess MR potentials in the evaluation of superior glenoid labrum disease and possible associated conditions of the rotator cuff and of the anterior mechanism of the shoulder. MATERIAL AND METHODS: We retrospectively evaluated 51 patients (age range 18 to 53 years) with a diagnosis of anteroposterior lesion of the superior glenoid labrum. MR examinations were performed with a 0.2 T permanent magnet and a dedicated coil, using T1- and T2-weighted SE sequences on mostly coronal-oblique planes. Slice thickness was 4 mm. In 8 cases, the examination was completed with intra-articular injection of contrast agent. Twenty-eight patients were submitted to surgery (arthrotomy in 7 cases; arthroscopy in 21 cases). RESULTS: We considered only the cases with surgical confirmation and divided them into 2 groups: 15 patients with isolated alteration of the superior glenoid labrum and 13 patients with an anteroposterior lesion of the glenoid labrum associated with disease of the rotator cuff or of the anterior mechanism of the shoulder. MRI demonstrated 5 cases of superior labrum irregularities at the level of its glenoid insertional portion (type I lesion); 6 cases of detachment of the superior portion of the labrum (type II); 9 cases of bucket handle tear of the superior labrum with involvement of the insertional portion of the long head of the biceps tendon (type III); 8 cases of superior labrum tear extending within the long head of the biceps tendon (type IV). In the patients with associated disease MRI demonstrated supraspinatus tendon tear in 5 cases, lesion of the labrum also in its anteroinferior portion in 1 case, Hill-Sachs intraspongious fracture with involvement of the inferior glenohumeral complex in 1 case, and complete tear of the rotator cuff in 7 cases. Subsequent surgery always confirmed the presence of associated lesions, while the superior labrum lesion was not confirmed in 3 patients. In 4 cases, surgical findings provided a different classification of the lesion type than MRI. DISCUSSION: In the presence of a type I anteroposterior lesion of the superior glenoid labrum, coronal MRI can depict the loss of the triangular shape of the labrum. Type II lesions show detachment of the labrum, which appears on the MR images as a high signal intensity band passing through the labrum with caudocranial orientation. A superior glenoid labrum tear with a low signal intensity area within the joint indicates a type III lesion. Complete tear of the superior glenoid labrum with involvement of the long head of the biceps tendon demonstrated on the coronal T1-weighted SE and T2-weighted GE sequences is a sign of a type IV lesion. CONCLUSIONS: MRI can be a valuable diagnostic technique in type III and IV lesions of the superior glenoid labrum. It often provides important information about the possible presence of associated diseases, especially of the rotator cuff, which are helpful for treatment planning.

Adolescent↗

PubMed2000

[Magnetic resonance angiography with contrast media bolus in the evaluation of aneurysms of the abdominal aorta].

PURPOSE: To investigate the potentials of 3D breath-hold contrast-enhanced Magnetic Resonance Angiography (MRA) in the diagnosis, follow-up and treatment planning of abdominal aortic aneurysms. MATERIAL AND METHODS: Twenty-four patients with infrarenal aortic aneurysm underwent MRA. We used a 1.5 T unit (GE Horizon, Echospeed 8.2), a phased array surface coil and 3D Fast SPGR T1-weighted sequences acquired on the coronal plane during patient breath-hold and after contrast agent i.v. administration. A bolus-test was done before angiography to optimize imaging delay time. After 3D MRA a Fast-SPGR T1-weighted sequence was acquired on the axial plane. The 3D MRA source images were processed with the MIP algorithm. Qualitative and quantitative analyses were carried out. Helical CT was performed in 6 cases and DSA in 7 cases. Surgery was the reference standard in 15 patients. RESULTS: MRA depicted aneurysm thrombosis in 22 cases, carrefour involvement in 18 cases and iliac arteries involvement in 3 cases. Accessory renal arteries were shown in 4 cases; iliac artery stenosis was associated in 5 cases. There was agreement between MR and Helical CT and DSA findings: surgery confirmed MRA results in 15/15 cases. CONCLUSIONS: 3D contrast-enhanced MRA can be considered the method of choice in the follow-up and treatment planning of abdominal aortic aneurysms, because it provides both angiographic and tomographic images: this allows to obtain more information, noninvasively and without the use of ionizing radiations.

Aged↗

PubMed2000

[Groin pain in athletes: role of magnetic resonance].

INTRODUCTION: Aim of our work was to evaluate the diagnostic role and potentials of Magnetic Resonance Imaging (MRI) in the study of groin pain in athletes and in the differential diagnosis among the pathological conditions that cause this syndrome. MATERIAL AND METHODS: MRI examinations were performed with a 1.5 T superconductive magnet, and a 0.2 T permanent magnet. Spin-Echo (SE) T1-w, PD, SE T2-w, Gradient-Echo (GE) T2-w and fat saturation sequences were used, on axial, sagittal and coronal scan planes. We performed MRI on twenty-five athletes (22 men and 3 women; age range 17 to 32 years) with chronic groin pain of questionable origin who had been complaining of it for at least 6 months. In 22 cases, radiographs were available; Computed Tomography (CT) had been performed in 3 cases and Ultrasound (US) in 7 cases. Nine patients were submitted to MRI after the symptoms had disappeared. RESULTS: In all patients, MRI provided an accurate depiction of pubic bone alterations and of adjacent myotendinous structures. In 14 cases, osteitis pubis was diagnosed, which was bilateral in 2 cases only (muscular asymmetry of the rectus abdominis was found in 4 of these patients); 4 patients had myotendinous posttraumatic changes (1 hematoma of the psoas muscle and 3 injuries of the abductor muscles of the thigh); 4 patients presented isolated dysmetria of rectus abdominis muscles, with unilateral involvement of the sacroiliac joint in 1 patient; 3 patients had inguinal hernia, surgically confirmed in all cases. DISCUSSION: Osteitis pubis, intended as reactive intraspongiuos edema of the pubic bones, is the most frequent cause of groin pain in athletes. In the early diagnostic phases, both plain films and CT may be negative or not specific. On the other hand, MRI has always proved to be a valuable diagnostic technique in detecting the osteitic change as an area of low signal intensity on T1-w images and of high and homogeneous signal intensity on T2-w scans without fat suppression. Dysmetria of the straight muscles of the abdomen, which may be associated, is always well depicted by MRI on axial planes. Both posttraumatic and dysmetric changes of the muscular structures adjacent to the pubis are well documented by US and MRI. The latter, however, thanks to its multiplanar capabilities, allows better spatial assessment of the alteration, especially if located at peri-insertional level. Possible associated diseases such as the involvement of the sacroiliac joints are also well shown by MRI. Inguinal hernias are easily demonstrated by MRI, which allows the direct visualization of the hernial sac within the inguinal canal. CONCLUSIONS: In our experience, only MRI can permit an accurate and early diagnosis of the different sport-related pubic conditions. MRI is also a valuable tool in monitoring the alterations with reference to their response to treatment, which may also help bring the athletes back to their activities.

Abdominal Muscles↗

PubMed2000

[Magnetic resonance imaging of hepatic focal lesions: dynamic contrastographic evaluation with gadolinium versus reticulo-endothelial hepato-specific contrast media].

PURPOSE: To compare the potentials of AMI-25 (Endoren) to those of Gadolinium with the dynamic contrast-enhanced technique in the differential diagnosis of focal liver lesions. MATERIAL AND METHODS: Forty patients with at least one focal liver lesion diagnosed at US underwent MRI. We used a 1.5 T unit and employed single-shot half-Fourier T2-weighted FSE and spoiled gradient-echo T1-weighted sequences before and after Gadolinium injection. Multiple acquisitions were obtained during the arterial, portal and delayed phases. Twenty-four to 48 hours later T2*-weighted GRE and SPGR/90 degrees sequences were obtained after AMI-25 administration. In the characterization of solid lesions the gold standard was biopsy performed with a shearing needle; for the diagnosis of angiomas and of 11 metastatic lesions we considered follow-up and clinical data as important diagnostic elements. RESULTS: We found 12 hepatocarcinomas, 14 metastases, 4 cases of focal nodular hyperplasia (FNH), 4 adenomas and 6 angiomas. The diagnosis was correct and confirmed by the conventional examination in all cases but 2 adenomatous lesions and 2 angiomas. Precontrast studies showed slight hyperintensity in 2 of 4 cases of FNH, while the other 2 lesions appeared isointense and were therefore detected only on postcontrast images, where there was contrast agent uptake during the arterial phase and rapid washout. We found only one central scar hyperintense on T2- and hypointense on T1-weighted images. After AMI-25 administration all lesions appeared isointense to surrounding parenchyma on T2* GRE sequences. Adenomas were isointense in the precontrast phase and postcontrast 3 of them showed strong Gadolinium uptake and rapid washout. After AMI-25 two of the 4 lesions were hyperintense while the other two were isointense to the parenchyma. Four of 6 angiomas exhibited a typical pattern characterized by signal hyperintensity on T2-weighted sequences and on AMI-25-enhanced T1- and T2-weighted sequences. Two angiomas were supposed to be of malignant nature but histology showed the presence of a strong fibrotic component. Hepatocarcinomas could be detected on precontrast images. After Gadolinium administration 10 lesions appeared hyperintense in the arterial phase and 2 were hypointense. After AMI-25 all lesions exhibited homogeneous signal hyperintensity and appeared slightly bigger than on Gadolinium-enhanced images. The metastases were only partly demonstrated by MRI. Postgadolinium studies showed 13 lesions with hyperintense signal in the portal phase. AMI-25 administration detected 14 lesions that appeared slightly bigger than on Gadolinium-enhanced images. CONCLUSIONS: AMI-25 can help also in characterizing primary lesions with an atypical signal pattern after contrast agent administration thanks to its intrinsic capability of accumulating in benign lesions. However it remains difficult to characterize well differentiated hepatocarcinomas and adenomas. Finally, AMI-25 improves MR capabilities in detecting secondary lesions and possible satellite nodules.

Adenoma↗

PubMed1999

Magnetic resonance angiography: state of the art.

The recently developed three-dimensional ultrafast sequences are able to acquire the entire aorta or the peripheral district in just 15 s. These sequences offer the possibility to obtain breath-hold images (that avoid breath artifacts) during the contrast medium peak. The technique is called three-dimensional angiography with contrast bolus. To perform the evaluation with this technique, high performance magnet units are needed (high magnetic fields, high gradient with fast ramping times). Clinical indications include the aortic district and especially thoracic aorta diseases and aortic dissections. This technique has great potentialities in the evaluation of the supra-aortic trunks, renal arteries and peripheral district. Shifting the table it is now possible to obtain the contemporary evaluation of both aorta and peripheral district with a single injection of contrast medium. The definition of the arterial district is comparable in many cases to that offered by digital angiography. The combination of magnetic resonance angiography and tomographic magnetic resonance technique is helpful for the endoluminal evaluation (as with digital angiography) and for the study of thrombi and wall as well.

Aortic Dissection↗

PubMed1999

[3-dimensional magnetic resonance angiography in apnea with the rapid infusion of a paramagnetic contrast medium in studying the thoracic aorta].

INTRODUCTION: We investigated the diagnostic accuracy of gadolinium-enhanced 3D MRA in the assessment of thoracic aortic diseases. MATERIAL AND METHODS: Thirty-eight patients with diagnosed or suspected conditions of thoracic aorta were examined with contrast-enhanced MRA. All the examinations were performed with a 1.5 T superconductive magnet acquiring breath-hold 3D fast Gradient-Echo (GE) sequences (TR = 5.9 ms; TE = 1.2 ms; FA = 45 degrees; FOV = 48 cm; thickness = 2-2.5 mm; locs = 30-32; TA = 22-24 s; MA = 512) on the coronal plane. The contrast agent was injected bolus after a bolus-test to evaluate circulation time. RESULTS: Three-dimensional gadolinium-enhanced MRA permitted to correctly diagnose aneurysm in 18 patients, dissection in 13 patients and coarctation in 3 patients. In the former the size and extent of the aneurysmal lumen and its relationship to aortic side branches was demonstrated. As for dissections we evaluated the following parameters: 1) type; 2) presence of intimal flap; 3) thrombosis of the false lumen; 4) dilatation of the aorta; 5) assessment of great vessel origins. MRA data were correlated with those of biplane transesophageal esophageal echocardiography, conventional MRI and spiral CT. In the three patients with aortic coarctation the site of coarctation was correctly identified, the degree of aortic narrowing evaluated and the collateral vessels demonstrated. CONCLUSIONS: In our opinion contrast-enhanced three-dimensional MR angiography should be the screening technique of choice in the evaluation of thoracic aorta thanks to its low invasiveness, short acquisition time, large field of view and morphologic resolution. ECG gating is not needed. Limitations are found in the study of wall and periaortic region which are better evaluated with conventional MR imaging.

Adult↗

PubMed1998

US and MRI in a case of persistent Müllerian duct syndrome.

We report the US and MR appearances in a case of persistent Müllerian duct syndrome, a rare form of inherited male pseudohermaphroditism characterised by the presence of uterus and fallopian tubes in a normally virilised 46XY male.

Child, Preschool↗

PubMed1998

Joint impingement syndrome: clinical features.

Joint impingement is a painful syndrome caused by the friction of joint tissues, which is both the cause and the effect of altered joint biomechanics. From the anatomical and clinical viewpoints, these syndromes are classified as bone impingement, soft tissue impingement and entrapment neuropathy, depending on what joint portion impinges on the others. We considered the most important impingement syndromes of the upper and the lower limbs from the clinical viewpoint. As for the upper limb, supraspinatus impingement is a frequent cause of shoulder pain in both athletes and the normal population; the painful subacromial arch is a typical sign of the rotator cuff impingement syndrome and of outlet and non-outlet impingement as well. As for the elbow, we considered both medial and lateral impingement. The carpal tunnel syndrome is the most common peripheral entrapment neuropathy of the upper limb; it is caused by compression of the median nerve at the wrist. We considered the main causes of carpal tunnel narrowing and the relative clinical findings. As for the lower limb, we considered the iliotibial band friction syndrome, which is the most common overuse syndrome of the knee and the ankle impingement syndrome. The latter includes anterolateral impingement (with chronic anterolateral and lateral pain and ankle instability), sinus tarsi impingement, anterior impingement (with pain during foot dorsiflection and posterior impingement. The tarsal tunnel syndrome is the most important ankle entrapment neuropathy causing burn pain and paresthesias in the toes and sole of the foot.

Cumulative Trauma Disorders↗

PubMed1998

Ankle impingement syndromes.

The ankle impingement syndrome is a frequent condition in both athletes and the normal population. We investigated this painful syndrome from both a clinical and a diagnostic viewpoint. Depending on what ankle tissue impinges on the other, it is possible to distinguish bone impingement, soft tissue impingement and peripheral nerve entrapment. For each of these pathologic conditions we investigated the diagnostic role of conventional radiography, Computed Tomography and Magnetic Resonance Imaging. The evidence of osteophytes, exostosis and presence of the os trigonum on plain films make clinical diagnosis easy in both anterior and posterior bone impingement. CT can provide useful information about the component of the posterior ankle. MRI always adds important information about chondral or subchondral bone injuries, synovial reaction and adjacent soft tissue involvement. The anterolateral impingement syndrome is caused by repeated injuries in plantar flexion and ankle intrarotation. MRI well detects the meniscoid injury thanks to high contrast sequences; it can also distinguish this syndrome from painful chondral and/or bony lesions at this level. MRI is also the method of choice to study sinus tarsi impingement, especially thanks to fat suppression sequences which increase MR diagnostic capabilities in this important anatomic area. Deep peroneal nerve entrapment, the medial plantar nerve entrapment syndrome and the tarsal tunnel syndrome are the most important entrapment neuropathies of the ankle. US and MRI are very useful to study the tendon and soft tissue abnormalities causing the anterior tarsal tunnel syndrome. CT and particularly MRI can easily detect many pathologic conditions causing the medial plantar nerve entrapment and the tarsal tunnel syndromes.

Ankle Injuries↗

PubMed1998

Diagnostic imaging of malignant cartilage tumors.

We compared the diagnostic capabilities of CT and MRI in the study of malignant cartilage tumors. Information about the characterization and the intra-/extraosseous spread of these lesions is of primary importance in the preoperative planning. Besides peripheral chondrosarcomas, arising from an osteochondroma and central chondrosarcomas, which are the most common malignant cartilaginous tumors, we also considered secondary, periosteal, dedifferentiated, clear cells and mesenchymal chondrosarcomas. Our study was performed using a standard MRI and CT protocol; in some cases, the examination was completed by the intravenous administration of a contrast agent. High contrast T2-weighted GE images can perfectly depict and differentiate the cartilage cap of an osteochondroma from the adjacent soft tissues. Evaluation of the growth of exostosis and of the thickness of its cap is essential in the assessement of malignant transformation. Both CT and MRI provide important information about peculiar aspects of the cartilaginous matrix such as the shape of calcifications-ossifications and lobulated growth, septa, septal enchancement and necrotic intratumoral areas, furthermore, CT perfectly shows the patterns of bone destruction. MRI should be considered as the most reliable imaging technique for the locoregional staging of malignant bone tumors thanks to its spatial and contrast resolution. CT plays a major role in the characterization of most bone tumors, especially those with a cartilaginous matrix.

Bone Neoplasms↗

PubMed1998

[Superparamagnetic iron oxide in the differential diagnosis of focal hepatic lesions using a 0.5-tesla magnetic resonance apparatus].

INTRODUCTION: We investigated the efficacy of superparamagnetic iron oxide (SPIO) in the characterization of focal liver lesions on MR images by means of quantitative and qualitative analysis. MATERIAL AND METHODS: We examined 60 patients with at least one focal liver lesion on US images. Conventional T1-weighted spin echo (CSE), proton density and T2-weighted MR images were acquired before and after the injection of a SPIO agent (Endorem, slow infusion, 15 micromoles Fe/kg body weight). A qualitative and a quantitative analysis were performed calculating the contrast enhancement rate in different kinds of lesions; the differences were related to the type of sequence statistically using Student's t-test for coupled samples. RESULTS: Excellent correlation was found with biopsy findings in all but two patients who were false positive for hepatocellular carcinoma (scar on cirrhotic liver). T1-weighted sequences after AMI-25 injection were the most specific ones in hemangioma characterization; PD were the most sensitive sequences in the detection and characterization of liver metastases. T2-weighted sequences were helpful only in the detection of focal liver lesions but they were not specific. CONCLUSIONS: In conclusion, SPIO-enhanced MRI is an excellent imaging tool for the differential diagnosis of focal liver lesions, with a good specificity for the differential diagnosis of hemangioma and metastasis. It is also helpful to distinguish benign from malignant lesions.

Contrast Media↗

PubMed1998

[Anterior cruciate ligament tears in athletes: assessment and clinico-diagnostic control with a dedicated system].

INTRODUCTION: We investigated the MR signs of anterior cruciate ligament (ACL) tears and tried to assess the patterns of both the acute and the chronic phases since more MR examinations are currently performed of the knee joint in the hyper and acute post-traumatic stage. MATERIAL AND METHODS: December, 1994, through September, 1997, a hundred and 89 sportsmen with a history of hyper and acute knee trauma were submitted to MRI: one hundred and four of them were followed-up for 3-6 months. The MR examinations were performed with a dedicated unit (Artoscan, Esaote Biomedica, Genoa) using T1-weighted SE, T2-weighted GE and Turbo ME sequences on the sagittal, coronal and axial planes, respectively (3-5 mm slice thickness). RESULTS: Of 189 patients examined in the hyper and acute post-traumatic stage, 101 had a complete ACL tear, 23 had a partial tear and 65 had an enlarged and inhomogeneous ACL: Eighty-five patients underwent surgery, while the other 104 had 3-6 months' follow-up MRI. Twenty-four of the latter had a complete ACL tear, 20 had a partial tear and 60 had no MR finding of ACL interruption, with a more or less inhomogeneous ligament. DISCUSSION: ACL tears are difficult to demonstrate in the acute phase because of perilesional swelling, synovitis and hemorrhage; high-contrast sequences on the axial plane are therefore required. In the chronic stage, an uninterrupted ACL does not necessarily imply that function is preserved, as well as the MR finding of a deflected ligament does not necessarily imply altered biomechanics. CONCLUSIONS: MRI of the knee joint is increasingly used to study hyper and acute ACL tears thanks to the availability of dedicated units. The MR study of ACL tears is not meant to refer the patients to surgery, which pertains to the physical examination, but it allows to assess lesion severity and to show associated injuries in other knee structures.

Acute Disease↗

PubMed1997

Overload syndromes of the peritalar region.

INTRODUCTION: The purpose of this study was to identify the diagnostic possibilities of the different diagnostic techniques in the evaluation of the pathological conditions affecting the peritalar region. MATERIALS AND METHODS: Between September 1995 and December 1996, 58 patients, with a painful syndrome at peritalar level were submitted to MRI, which was performed using a 'dedicated system' consisting of 0.2 and 0.5 T equipment. Spin-Echo T1-weighted and Gradient-Echo T2-weighted sequences were used on sagittal, coronal and axial planes, with slice thickness of 3-5 mm. Conventional radiography was previously performed in all patients, while 18 of them underwent CT. Surgery or arthroscopy was performed in 22 cases. 36 patients underwent clinical follow-up associated with conventional radiography in six cases, MRI in 11 and to both of them in six patients. RESULTS: After arthroscopy and surgery, an involvement of the tibio-talar joint was found (one pathogenic synovial plica, three meniscoid syndrome and 12 anterior impingement) in 16 patients. Concerning the subtalar joint, surgical examination revealed a cellulo-adipostis of the sinus tarsi in two patients, while in three cases osteochondral damage of the subtalar joint was identified. In the last patient, degenerative changes of the posterior tibial tendon associated with osteochondral pathology of the talo-navicular joint were found. MRI findings agreed with the surgical and arthroscopic ones in all patients except for the synovial plica; in this case, the MRI was negative. Follow-up performed on 36 patients revealed 12 tibio-talar joint, 17 subtalar joint and 7 talo-navicular joint pathological conditions. DISCUSSION: Concerning the tibio-talar joint, MRI findings were confirmed by arthroscopy in all cases of anterior impingement. Magnetic resonance (MR), due to its capability in detecting osteochondral damage and identifying osteophyte sites, results in the best imaging method for evaluating this condition. Meniscoid syndrome is easily detected by MRI only in the presence of sufficient scar tissue, while conventional radiography reveals the calcific stage. In sinus tarsi syndrome, the ligamentous damage associated with sero-hemorrhagic effusion at fatty tissue level may lead to a 'chopping' effect on the nerve endings: this condition is well demonstrated by MRI. In all cases of osteochondral alterations affecting both the subtalar and talo-navicular joint, it has been possible to obtain correct diagnosis with MRI, which also depicted well the tenosynovitis of the posterior tibial tendon. In cases of stress fracture of the navicular bone, both CT and MRI demonstrated the lesions well, even when, in the early phases, conventional radiography produced a negative result. In conclusion, MRI may be considered the choice method in the study of different pathological alterations affecting the peritalar region, also providing detailed information useful for a therapeutic approach.

Adult↗

PubMed1996

Dedicated MR system and acute trauma of the musculo-skeletal system.

MRI diffusion in the osteoarticular field is limited by the high costs of whole-body systems. Recent technological advances have allowed the development of cost-effective and easy-to-install dedicated MRI systems. One such system, which can only be employed for the study of limbs, is based on a 0.2-T permanent magnet. Acute trauma of the musculo-skeletal system represents an important area of application. Over a period of 2 years, 1258 patients with acute trauma of the joints (64%) and the periarticular bones (36%) have been studied. Satisfactory results, comparable to those from whole-body scanners operating at higher magnetic fields, were obtained. Acute painful syndromes did not represent an obstacle to the performance of the examination. Only in 2% of patients was it not possible to carry out the examination due to oversized limbs or complete articular blocks. On the basis of these considerations, it may be predicted that in the near future dedicated MR systems will find increasingly wide application in the field of musculo-skeletal traumatology.

Acute Disease↗

PubMed1996

[Gastric adenocarcinoma: magnetic resonance versus surgical staging].

Preoperative MR staging in 34 patients with gastric adenocarcinoma was compared with postoperative histologic findings to evaluate MR sensitivity, specificity and accuracy. MR exams were carried out with an 0.5-T superconductive magnet, with SE T1- and T2-weighted sequences on axial and sagittal planes, 10-mm slice thickness and 3-mm interval. The stomach was distended with a watery solution of Gd-DTPA. MRI showed the tumors only in their advanced stage. MR sensitivity was high in detecting hepatic metastases, but peritoneal carcinomatosis was difficult to demonstrate because of inherent technical MR limitations, such as motion and respiratory artifacts. MRI had 40.6% sensitivity, 93.87% specificity and 42.08% accuracy in demonstrating lymph node involvement. Hepatoduodenal lymph nodes were particularly difficult to study, as were those in the splenic hilum and artery. No correlation was found between tumor invasion and lymph node size. MRI exhibits many limitations in gastric carcinoma staging because of motion and respiratory artifacts and of the long acquisition times needed for gastric studies. However, MR sensitivity and specificity are similar to those of CT, as reported in the literature.

Adenocarcinoma↗

PubMed1995

[Technologic advances in magnetic resonance imaging: permanent low-field magnets dedicated to the study of the joints. Clinical results].

Magnetic Resonance Imaging (MRI) has had a significant impact on the diagnosis of musculoskeletal conditions. Technologic advances in the last years allowed the development of cost-effective, compact and easy-to-install MR systems. After an early phase to optimize the units, a 14-month multicentric study was performed to define the possible clinical applications of the system. The obtained data are reported by the authors in the present study to assess the diagnostic accuracy of the new MR system for the study of the limbs. The system consists of an 0.2 T permanent unit, weighting 800 Kg, with a built-in radiofrequency shield and 10 mT/m gradients. October, 1992, to February, 1994, 2437 limbs examinations were carried out in patients whose age ranged 5 to 83 years. In 93% of cases, the exam was performed to study one joint, mostly the knee. MR diagnosis was verified in 311 patients, who were subsequently submitted to surgery. Quite satisfying overall results were obtained, particularly in case of knee traumas, comparable to those provided by units with more potentials. The particular structure of the magnet allowed the comfortable management of the pediatric, aged and acute patients. Nevertheless, in 3% of the investigated knee or elbow conditions, the examinations could not be performed due to technical limitations related to magnet size. In addition, the authors believe that a limited field of view (11-16 cm) does not allow accurate staging of the malignant lesions involving soft tissue and bone, which require a wider locoregional staging.

Adolescent↗